303 



Caret' uiiibellafa 

 Potentilla arguta 

 Asclep'ias ample xicaulis 

 SUene antirrhina 



Polygonum temic 



Salix glaucophylla 

 /uncus balticus littoralis 

 Cycloloiua atriplicifoHum 

 Andropogon scoparius 



Aster aznreus 



Rudbeckia hirta 



Solidago nenwraUs 



Panicum huachucae (in blowing 



sand) 

 Tradescantia reflexa 

 Liatris cylindracea 



Relic Species 

 Koeleria cristata 

 Lithospennuiii gmclini 

 Panicum rirgatum 

 Calam ovilfa longi folia 



Relic species persisting in places in which this association develops 

 after oaks have been cleared off 

 Anemone cylindrica Sinilaciiia stcUata 



Helianthus occidentalis Hieraciitin canadcnse 



Lupinus pcrennis 



Invading Species 



Arctostaphylos uva-ursi 

 Juniperits horisontalis 

 Betida alba papyrifera 

 Potentilla fruticosa 

 Lobelia s pi cat a 

 Linum z'irginianum 

 Aster ptarmicoidcs 

 Petalostemum candidum 

 Petalostemuni purpureum 



Coinandra umbellata 

 Silphium integrifoHum 

 Ouercus vclutina 

 Rhus toxicodendron 

 Frag aria virginiana 

 Asparagus officinalis (avevectant 

 nnder very small Q. velutvna) 

 Poa cornpressa 



THE POA COM PRESS A ASSOCIATION 



The sand-plain which stretches inland from the limit of storm 

 wave-action, particularly from the state line to Kenosha, is char- 

 acterized by a light sod of English blue grass {Poa compressa) rather 

 than by blazing star {Liatris scariosa) or black oak. Farther inland 

 this association may also occur on ridges from which the black oaks 

 have been removed. 



Physical Characteristics. — The ground on which this association 

 occurs is quite pure sand, made more or less yellowish by the admix- 

 ture of a substance which tends to cement the sand grains together. 

 Occasionally there are deposits of what appears to be guano, al- 



